Toner or process cartridges for laser printing are engineered and manufactured to a high degree of precision necessary for proper operation and good printed image quality. Central to proper operation of a toner cartridge is the maintenance of alignment and orientation of its various components. Original equipment manufacturers achieve the rigidity necessary to maintain the alignment and orientation of components, in substantial part, by ultrasonically welding the sections of the toner or process cartridge together. The process of remanufacturing a toner or process cartridge requires that the cartridge be disassembled and that the hopper section of the cartridge which holds the toner be separated from the roller section which contains the developer roller and other components. When the hopper and roller sections are separated, however, precise alignment and orientation of performance critical components—including particularly that between the developer roller and sealing blade and/or between the developer roller and developing blade may be lost.
Heretofore, a problem has existed in aligning the sealing blade and/or the developing blade with the developer roller with the necessary precision during reassembly of the hopper and roller sections. The conventional approach to this problem has been to manually carefully align and fit the two sections together, with or without the aid of a positioning jig, then to manually secure the sections together with a number of metal clips. Alternatively, the sections maybe fastened together with adhesive or glue. This technique, while generally effective suffers a number of drawbacks.
A primary drawback is that both metal clips and adhesive are consumables which increase production costs and cost of the final product. Another significant drawback is that manual reassembly is quite labor intensive and is subject to human error and variation in quality. In the case of reassembly with adhesive or glue, there typically is a period of a few to several minutes for bonding to take place during which alignment must be maintained, and which increases production time and cost. Further, resealing with adhesive often fuses or bonds the sections together, rendering subsequent separation for additional remanufacturing cycles difficult or impossible.
An additional drawback in the use of metal clips to reassemble the cartridge is that the rigidity imparted by the original ultrasonic weld is difficult to achieve, and over the working life of the cartridge the clips may loosen or become disengaged entirely. In such event, as a result of loss of proper alignment of the sealing blade and/or developing blade with the developer roller, excessive toner may accumulate on the developer roller with the result that a mass of excess toner will be transferred to the photoconductive printing drum and thence to the printer paper thereby degrading the printed image quality. Further, disengagement of a metal clip may permit toner to leak from the cartridge. In many printing devices (such as printers, facsimile machines or copiers), the path of the paper through the printing device passes nearby to an edge of the toner cartridge where the metal clips have been installed. Hence, papers jams may occur if a loose metal clip projects into the paper path.
Although toner cartridges manufactured from new components by original equipment manufactures typically are sealed by ultrasonic welding, that technique has until now been unavailable for use in the remanufacture or reassembly of toner cartridges. A primary impediment to the use of ultrasonic welding in the rejoining of the hopper section and roller section of a toner cartridge during reassembly has been the absence of an energy director element. Briefly, an energy director element is a relatively small feature—typically in the form of a ridge or bump—which extends slightly above the surface of the surrounding area and contacts the surface to be welded. The energy director is of the same material as the remainder of the plastic component and is formed in the mold in which the plastic component is created. During the ultrasonic welding process it is the energy director element which is first melted primarily as a result of the friction created between the two surfaces to be welded caused by the ultrasonic vibrations. It is the melting together of the surfaces to be bonded at the location of the energy director element which, upon cooling and solidification, welds the two surfaces together. Thus, the energy director element is largely or entirely consumed or destroyed in the sealing together of the hopper section and roller section in the original manufacture of a new toner cartridge. Hence, upon separation of the hopper and roller sections at the location of the original ultrasonic weld during the remanufacturing process, there no longer exists an energy director element from which to initiate ultrasonic welding to rejoin or reseal the these components.
The present invention is directed to solving these problems by providing a reassembled toner cartridge and method of manufacture in which the hopper section and roller section are ultrasonically welded together without the necessity of an energy director element, and without the need for or use of consumable components.